1. Field of the Invention
The present invention relates to a method of manufacturing a liquid ejection head.
2. Description of the Related Art
One example of the liquid ejection head includes an ink jet recording head to be applied to an ink jet recording method of performing recording by ejecting ink to a medium to be recorded. A method of producing the ink jet recording head includes a method in Japanese Patent No. 3143307, for example. According to the method, a positive photosensitive resin layer laminated on a substrate is exposed, development is performed to form a mold material of an ink channel, a coating layer which covers the mold material is provided, and then the coating layer is exposed to form ejection ports. The positive photosensitive resin is removed, and then the coating layer is cured to produce the ink jet recording head.
Japanese Patent No. 3143307 discloses forming the positive photosensitive resin layer on a substrate provided with a supply port. Specifically, a solution in which the positive photosensitive resin is dissolved in a suitable solvent is applied onto a film of PET (polyethylene terephthalate) or the like, and then dried to produce a dry film. Then, the dry film is transferred by a lamination method. Moreover, it is disclosed that a vinyl ketone photodegradable resist, such as polymethyl isopropenyl ketone or vinyl ketone, which has a coating property as a high molecular weight compound before irradiation with light, and can be easily laminated on the supply port is preferable as the positive photosensitive resin. Furthermore, as the positive photosensitive resin, a photodegradable resist having solvent resistance is used from the balance with a coating layer material.
On the other hand, the variation of the ink jet recording head has increased in recent years. As the film thickness of the positive photosensitive resin layer serving as the mold material of the ink channel, the film thickness exceeding 15 μm is required in many cases. Particularly in this case, the energy required for exposure is high, the generation of decomposed matter of the photodegradable resist is not negligible. The decomposed matter contaminates the inside of an exposure apparatus, particularly adheres to an exposure mask to scatter light to cause reduction in patterning properties. Therefore, in a manufacturing process, washing of the mask is periodically required, so that the production efficiency sharply decreases due to the washing of the mask. A method of preventing the contamination of the inside of the exposure apparatus caused by gas generated from the resist in such exposure includes a method described in Japanese Patent Laid-Open No. 2005-242318. Japanese Patent Laid-Open No. 2005-242318 discloses a method of forming, on a chemistry amplification type resist film, a water-soluble film containing a water-soluble polymer whose gas permeability is lower than that of the resist, and then performing pattern exposure to thereby capture the gas generated in the exposure by a water-soluble polymer.